1. Field of the Invention
The present invention is directed to a tank system for storage and agitation or circulation of fluids. In particular, the present invention is directed to a tank system for storage of drilling fluids used in drilling wells. The present invention is directed to a tank system with maximum efficiency from mechanical agitators to produce a mixing action for chemicals and solid materials in suspension. The present invention also includes an innovative heat and fume removal system.
2. Prior Art
Mud tanks and mud tank systems are widely employed and known in the drilling, workover and mining industries. As an example, in the drilling industry, drilling may be performed for oil or gas wells or for water wells. In a typical process for a subterranean well bore, a bore is drilled into an earth formation.
Oftentimes, a drilling fluid is circulated from the surface, down through a drill string, and down to a drill bit. The drilling fluid absorbs heat generated by action of the drill bit. Thereafter, the drilling fluid passes up through an annular area to a return receptacle at the surface. The return drilling fluid carries with it earth particles and drill cuttings which are separated out in various ways at the surface, such as with a shale shaker. Other processing equipment, such as a degasser may also be used. After processing, the drilling fluid is then stored at the surface for reuse.
This drilling fluid or "mud" acts as a lubricant, a sealant to maintain downhole pressure, a coolant for the drill, and a hydraulic carrier of cuttings. The drilling fluid is retained in a mud tank and both stored for reinjection of the drilling fluid down through the drill stem. The storage tanks typically include a mechanism to agitate the fluids and keep the constituents from separating. The agitation of the fluids in the storage tank also serves to dissipate heat retained in the fluids.
Rectangular or square storage tank designs have traditionally been used for storage of drilling fluids. The fluids must be agitated throughout the tank during storage to avoid fluids from being stuck in a "dead" corner. Often a simple metal grate encloses the open top. Personnel are not shielded from the heat or fumes released from the drilling fluid.
At least two types of drilling mud are employed-water based mud and oil based mud, including synthetic variations. With oil based mud, it is desirable to keep the elements such as rain, snow or ice from mixing with the drilling fluid. At the same time, it is desirable during storage to ventilate the fluid to allow for cooling and discharge of fumes. The drilling mud may reach plus 180.degree. F. after being circulated downhole.
It is, therefore, a principal object and purpose of the present invention to provide a tank system for storage and agitation of drilling fluid having a combined cover and walkway to protect the fluid from the elements and provide personnel with a platform.
It is also a principal object and purpose of the present invention to provide a tank system for storage and agitation of drilling fluid which will enhance the agitation of the fluid during storage and will provide a natural drainage system to allow drainage of said tank.
It is a further object and purpose of the present invention to provide a tank system for storage and agitation of drilling fluid having a heat and fume removal system.